Question

己知二次函数y=x²+mx+3的图像的顶点在x轴上,则m的值为？

Answer 1

解答:y'=2x+m=0，x=-m/2这时y=0
则0=0.25m²-0.5m²+3
m=±2根号3

Answer 2

y = x²+mx+3 = (x+m/2)² + 3 - m^2/4
y(-m/2) = 3 - m^2/4 = 0, m = ±2√3